Polyolefins stabilized with reaction products of nonylphenol and carbonyl compounds



POLYGLEFINS STABILIZED WITH REACTION PRODUCTS ()F NONYLPHENOL AND CAR-BDNYL COMPOUNDS Felix Schiilde, Bad Sodeu (Taunus), and Otto Mauz,Frankfurt am Main, Germany, assignors to Farbwerke HoechstAktiengesellschait vormals Meister Lucius & Briining, Frankfurt am Main,Germany, a corporation of Germany No Drawing. Filed Sept. 3, 1958, Ser.No. 758,690 Claims priority, application Germany Sept. 7, 1957 6 Claims.(Cl. 260-4535) The present invention relates to a process forstabilizing polymers of low pressure olefins.

The polymerization products of olefins of high degree of polymerizationhave gained an'increas'ing industrial importance in the last years. Themacromolecular compounds have thermoplastic properties, that is to saythey can be shaped in various ways under the action of heat andpressure. There may be produced by means of suitable devices filaments,films, blocks, plates, hollow bodies and like structures. In the courseof said processing, which is carried out at elevated temperature, adegradation of the polymer chains takes place and fractions of themacromolecule are formed which impair the technological properties ofthe starting material, such as stability,

quaternary carbon atoms which, as known from reactions of low molecularcompounds, possess an increased reactivity.

Said instability of the polymers has already been ob-- served in thecase of polyethylene prepared under high pressure and at elevatedtemperature in the presence of oxygen or peroxides as catalysts. Anextensive literature exists with regard to compounds having beenexamined as stabilizers for said polymer. Various classes of chemicalcompounds have been found to be effective.

Phenol derivatives, amines, sulfur and organic sulfur compounds havebeen proposed as stabilizers. Furthermore there have been mentionedorganic and inorganic pigments such as silicic acid, silicates, soot,and other organic and inorganic pigments which are simultaneouslydyestuffs.

A stabilizer complying with the requirements of practice shall have thefollowing properties:

(1) It shall protect the polymer from degradation when the latter issubjected for a prolonged period to the action of light and/or elevatedtemperatures, above all in the presence of oxygen.

=(2) It shall not discolor the polymer even at higher temperatures.

(3) It shall not migrate out of the polymer.

(4) It shall have a poor volatility and no odor.

(5) It shall be physiologically harmless.

(6) The amounts of stabilizer required for an efiective protection ofthe polymer shall be small.

A great number of stabilizers is known for polymerization products ofethylene produced by the high pressure process mentioned above. In US.Patent 2,434,662 there are mentioned for example phenol derivatives suchas this kind are preferably prepared by the low pressure diphenylolpropane and discresylol propane. In US.

Patent 2,538,355 similar derivatives of methane are described containingalkyl radicals of 1-8 carbon atoms bound to the benzene nucleus. InCanadian Patent 470,325 the condensation products of phenol andcyclohexanone are described as effective stabilizers for high pressurepolyethylene.

Furthermore in US. Patent 2,675,366 there are disclosed2,2'-methylene-bis-4,6-dialkyl phenols as stabilizers for polyethylene.Australian Patent 4,110/54 describes sulfur-containing phenolderivatives, for example the 4,4-thio-bis-(6-tert.-butyl-m-cresol),displaying a good stabilizing effect for high pressure polyethylene.

Said compounds known as stabilizers for high pressure polyethylenepractically fail to'work in the case of a new class of polymericolefins, namely the so-called low pressure polyolefins as' disclosed inBelgian Patents 533,362, 534,792, 534,888, 540,459, Italian Patent 526,101 and Irish Patent 668/55. The processes for the manufacture of lowpressure polyolcfins are described in detail by Ralf Allison,Polyethylene, 1956, pages 72-81 and particularly pages 7782. Forexample, the said low pressure polypropylene or polybutene-l may beprepared by the polymerization of propylene or butene-l in the presenceof a catalytic amount of a catalyst prepared from a mixture of anorgano-aluminum compound and a salt of a heavy metal of subgroupsIVb-VIb of the periodic table. I I

Now We have found that the reaction products of nonyl phenol withcarbonyl-containing organic compounds obtained with the use of mineralacids as dehydrating agent. surprisingly constitute .an excellentstabilizer for polymers produced from olefins having tertiary carbonatoms. As nonyl phenol there may be used an industrial productsubstantially consisting of p-nonyl phenol. In one portion of themolecules the nonyl chain is straight and in another portion branched.The nonyl component for the nonyl phenol is prepared, for example, bytrimerization of propylene according to a process described by Anzis andPetrow in: Reports of the Academy of Sci ences, U.S.S.R., 70 .(1950),page 425. As carbonyl-containing compounds for the production of thereaction product with nonyl phenol used as stabilizer in the process ofthe invention there are suitable, for example, formaldehyde,acetaldehyde, acetone, methylethyl ketone, cyclohexanone, benzaldehyde,i.e. there may be used straight chain as well as cycliccarbonyl-containing organic. compounds having-either an aldehyde or aketone character. It is of advantage to employ acetone for theproduction of the stabilizer used in the process of the invention.v Forthe aforesaid polymers produced from olefins having tertiary carbonatoms there is particularly effective as stabilizer thebis-(nonyl-hydroxyphenyD-propane formed in the reaction mixture whencondensing nonyl phenol with acetone. In the following the condensationproduct bis-(nonyl-hydroxyphenyl) propane is named dinonyl-diane.

The dinonyl-diane is an oil which is distillable at 210 C. under apressure of 0.1 mm. of mercury. The distillate constitutes a veryviscous liquid.

As mineral acids favoring the splitting off of Water in the condensationof nonyl phenol with carbonyl-containing compounds there may be usedhydrochloric acid of 35% strength or hydrochloric acid gas which isintroduced into the reaction mixture until the organic phase issaturated (acetone absorbs hydrochloric acid gas) or sulfuric acid of10-70% strength. As polymers which can be stabilized with the reactionproduct according to the invention of nonyl phenol withcarbonyl-containing compounds there are suitable polymers that have beenproduced from olefins containing tertiary carbon atoms, for examplepolypropylene or polyb-utene. Polymers of process described by Ralf,Allison, Polyethylene, 1956, pages 72-81, particularly page 78 and seq.There may, of course, also be stabilized by the process of the inventioncopolymers of propylene (which contains tertiary carbon atoms) withethylene (which does not contain tertiary carbon atoms) since copolymersof this kind contain tertiary carbon atoms in the macromolecule in alarger amount and in regular sequence. The tertiary carbon atoms in themacromolecule are probably respon' sible for a high sensibility of thepolymers with respect to oxygen, particularly at elevated temperaturesor under the action of light.

Said sensibility becomes apparent by the reduction of the specificviscosity of a sample or the tendency to become brittle of shapedarticles or also by the absorption of oxygen by the polymer.

The fact that high pressure polyethylene difiers from the aforesaid newclass of olefin polymers in the degradation behavior seems to beself-evident. High pressure polyethylene which can be well stabilized bymeans of the substances already described has a much smaller number ofbranchings as compared with the aforesaid polyolefins in which eachsecond carbon atom may be tertiary. Quantitative analysis of ultra-redspectra of high pressure polyethylene showed for example 21.5 methyl and14 ethyl branchings per 1000 carbon atoms (D.C. Smith, Ind. Engng. Chem.48/7 (1956), page 1161), that is to say in the case of weakly branchedhigh pressure polyethylene the content of tertiary carbon atoms in thechain is about one order of magnitude smaller than, for example, in thecase of polypropylene or polybutylene.

The stabilizer of the present invention largely complies with therequirements described above.

The efiective concentration of the stabilizer varies be tween 0.05 andpreferably between 0.3 and 1.0%. In general, an amount of 0.5% of thereaction product of nonyl phenol with carbonyl-containing compounds isfully sufficient in order to obtain a permanent stability of thepolyolefins mentioned.

The polyolefins having tertiary carbon atoms are best admixed with thestabilizer according to the invention by way of a mixture consisting ofa large amount of stabilizer and a small amount of polyolefin (masterbatch).

It is of course likewise possible to incorporate the stabilizer of theinvention into the polymerization prodnets in the course of theirproduction or their working up. Said mode of operation offers thespecial advantage that the polymer is early protected against the actionof light or atmospheric oxygen, particularly at higher temperatures,that is to say already in the course of the preparation or working up.

Moreover it is possible to introduce the reaction product of nonylphenol with carbonyl-containing compounds into the aforesaid polymerstogether with known antiagers or processing auxiliaries. In admixturewith other stabilizers there may be obtained, in some cases, asynergistic efiect. As additives of this kind there may be employedalkyl-substituted phenols and naphthols such as2,6-di-tert.butyl-p-cresol, nonyl-fl-naphthol etc.; aliphatic andaromatic thio-ethers such as bis-(4-hydroxy-2-methyl-5-tert.butyl-phenyl)-sulfide; N-alkylor N,N-dialky-l derivativesof p-phenylene diamine; N-acyl derivatives of p-amino-phenol andcompounds such as bis-(2,4,6- trihydroxy-phenyl) -sulfide,bis-t(hydroxy-nonyl-naphthyl)- sulfide,bis-(hydroxymethyl-sec.propyl-phenyl) -sulfide anddithio-phenol-Z-carboxylic acid.

The polyolefins having tertiary carbon atoms in regular sequence andcopolymers made from at least one starting component possessing tertiarycarbon atoms which have been stabilized in this manner can be processedby known molding methods such as pressure, injection or extrusionmolding processes. When the polymerization products treated as describedabove are tempered at 100 or 120 C. they become brittle after aconsiderably longer time than polymers stabilized in the same mannerwith known substances of the indicated class. 7 It can likewise beobserved that the degradation of the material, measured by the decreaseof the reduced viscosity, is considerably smaller than in the case ofthe corresponding comparison mixtures.

The following table gives the periods of embrittlement at 120 C.measured for polypropylene, polybutene and low pressure polyethylene(for the purpose of comparison) containing each time 0.5% of thestabilizer indicated. The time of embrittlement is the period in daysafter which a pressed film of polyolefin having a thickness of 1 mm.breaks on bending.

STABILIZATION 0F POLYPROPYLENE, POLYBUTENE, LOW PRESSURE POLYETHYLENEpolypropylpolybutene-(l) low pressure stabilizer enc embritcolor andgeneral embrittlement] color and genpolyethylene color and generaltlernent in behavior days eral behavior embrittlebehavior days ment indays 4,4-dihydroxydiphenyl-di- 40 sticky, slightly 27 sticky, slightly25 colored.

methylmethane. colored. colored. di-o-cresylol propane 20 slightlysticky..- 15 slightly sticky--- 17 Do. dil-lmydroxyphenyl) -cyclo 25slightly colored.- l0 slightly colored- 15 Do.

exane.

dioctyldiane 32 --do 17 -...do 25 slightly colored. reaction product ofnonyl- 200 no coloration, 172 no coloration, 32 no coloration.

phenol with acetone. no stickiness. no stickiness.

For this purpose a concentrated solution (of about strength) of thereaction product of nonyl phenol with carbonyl-containing compounds inacetone or methylene chloride, for example, is mixed with a small amountof the powdery polymerization product to be stabilized in a proportionsuch that, after the evaporation of the solvent, the mixture containsabout 15-40% of stabilizer. When operating in this manner there isobtained a dry powder which can be blended in usual manner into thepolymer to be stabilized. Thus the concentration of the stabilizer inthe final mixture can be adapted to the requirements.

advantage consists in the fact that the reaction product of nonyl phenolwith acetone is excellently compatible with the polyolefins to beconsidered. In the course of the aging or while tempering an emigrationof the incorporated stabilizer out of the polymer has in no case nonylphenol with acetone is the great fastness to light and color fastness ofthe polymers stabilized therewith. drating agent, with formaldehyde.Polypropylene or polybutene stabilized with the aforesaid substance doesnot change its color to a noteworthy degree on tempering or onirradiation.

Measurements of the reduced viscosity prove that practically nodegradation takes place when tempering polymers of the kind mentionedabove which have been treated with the stabilizers of the invention.

Also in comparison with usual stabilizers having a'differentconstitution the stabilizers of the invention exhibit variousadvantages. All known stabilizers cause a discoloration of the materialon tempering a polymer of the aforesaid class which has been stabilizedtherewith. Furthermore no antiager has been known which does not changethe surface structure on tempering. These detrimental phenomena can bedone away with by stabilizing with the stabilizers according to theinvention.

The following example serves to illustrate the invention but it is notintended to limit it thereto.

Example Low pressure polyethylene (for the sake of comparison), lowpressure polypropylene and low pressure polybutene were thoroughly mixedwith 0.5% each of the following antiagers (a) Reaction product of nonylphenol with acetone (b) 4,4'-dihydroxy-diphenyl-dimethyl-methane (c)Di-o-cresylol propane (d) Di-(hydroxy-phenyl)-cyclohexane (e) Reactionproduct of nonyl phenol with formaldehyde (f) Reaction product of nonylphenol with acetaldehyde From these mixtures sheets having a thicknessof 1 mm. were prepared by the pressure molding process.

From the same mixtures bands having a thickness of about 2 mm. and awidth of 5 cm. were produced by the extrusion molding. The major part ofthe bands was granulated and from the granules sheets of 1 mm. thicknesswere produced by injection molding.

The pressed sheets, the extrusion bands and the injection molded sheetswere tempered at 120 C. and the time was determined in which the sheetsbecame brittle. The following table gives the periods of embrittlementobserved.

of a catalyst prepared from a mixture of an organoaluminum compound anda salt of a heavy metal of subgroups IVb-Vlb of the periodic'table, andODS-5% by weight of the product formed by the reaction of nonyl phenol,in the presence of a mineral acid dehydrating agent, with a memberselected from the group consisting of formaldehyde, acetaldehyde,acetone, methylethyl ketone, cyclohexanone and benzaldehyde.

2. As a new composition of matter, a solid copolymer of ethylene with amember selected from the group consisting of propene and butene-l, atleast one repeating unit of the copolymer containing tertiary carbonatoms, said copolymer being prepared by the polymerization of theaforesaid olefins in the presence of a catalytic amount of a catalystprepared from a mixture of an organoaluminum compound and a salt of aheavy metal of subgroups IVb-Vlb of the periodic table, said copolymercontaining ODS-5% by weight of the product formed in the reaction ofnonyl phenol, in the presence of a mineral acid dehydrating agent, witha member selected from the group consisting of formaldehyde,acetaldehyde, acegorge, methylethyl ketone, cyclohexanone and benzalde-3. Solid low pressure polypropylene stabilized with 0.055% by weight ofthe product formed in the reaction of nonyl phenol in the presence of amineral acid dehydrating agent, with a member selected from the groupconsisting of formaldehyde, acetaldehyde, acetone, methylethyl ketone,cyclohexanone, and benzaldehyde, said polypropylene being prepared bythe polymerization of propylene in the presence of a catalytic amount ofa catalyst prepared from a mixture of an organo-aluminum compound and asalt of a heavy metal of subgroups IVb-Vlb of the periodic table.

4. Solid low pressure polybutene-l stabilized with ODS-5% by weight ofthe product formed in the reaction of nonyl phenol, in the presence of amineral acid dehydrating agent, with a member selected from the groupconsisting of formaldehyde, acetaldehyde, acetone, methylethyl ketone,cyclohexanone and benzaldehyde, said polybutene-l being prepared by thepolymerization of butene-l in the presence of a catalytic amount of acatalyst prepared from a mixture of an organo-aluminum compound and asalt of a heavy metal of subgroups IVb-VIb-of the periodic table.

5. As a new composition of matter, a solid polymer produced from anolefin selected from the group consisting of propene and butene-l, saidpolymer containing tertiary carbon atoms and being prepared by thepolymerization of the olefin in the presence of a catalytic PERIODS OFEMBRITTLEMENT IN DAYS polypropylene polybutene-(l) low pressurepolyethylene (for comparison) untiager press extrusion injection pressextrusion injection press extrusion injection sheet band sheet sheetband sheet sheet band sheet reaction product of nonyl phenol 4 gnggceitpnen n un hdf.ti 200 200 -150 172 167 30-95 32 30 5yoxeny-melmethaneiof 40 35 15 27 20 11 25 12 7 di-o-cresylol propane 2021 12 15 15 7 17 18 7 d1- (hydroxyphenyl)-cyclohexane 25 21 13 10 11 715 7 10 reaction product of nonyl phenol and formaldehyde -l50 50-130160 150 30490 reaction product of nonyl phenol and acetaldehyde," -15050-130 160 150 30-90 without addition 1-2 1 1-2 1 2-4 2-4 We claim:amount of a catalyst prepared from a mixture of an or- 1. As a newcomposition of matter, a solid polymer produced from an olefin selectedfrom the group consisting of propene and butene-l, said polymercontaining tertiary carbon atoms and being prepared by thepolymerization of the olefin in the presence of a catalytic amountgano-aluminum compound and a salt of a heavy metal of subgroups IVbVIbof the periodic table, and 0.05%5% by weight of the product formed bythe reaction of nonyl phenol, in the presence of a mineral aciddehydrating agent, with acetone.

'ing of propeneand butene-l, said polymer containing 6. As a newcomposition of matter, a solid polymer References Cited in the file ofthis patent produced from an olefin selected from the group consist-UNITED STATES PATENTS tertiary carbon atoms and being prepared by thepoly- 2,434,662 Latham et a1 20! 1948 merization of the olefin in thepresence of a catalytic 5 2,731,442 Formal] 17, 1956 amount of acatalyst prepared from a mixture of an 2324990 Edwards et a1 18, 1958organo-aluminum compound and a salt of a heavy metal 2,833,755 CooverMay 1958 of subgroups IVb-VIb of the periodic table, and 0.05

5% by weight of the product formed by the reaction of FOREIGN PATENTSnonyl phenol, in the presence of a mineral acid dehym 470,325 CanadaDec. 26, 1950 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONPatent No. 3,020,259 February 6, 1962 Felix Schiilde et al.

he above numbered pat- It is hereby certified that error appears in tPatent should read as ent requiring correction and that the said Letterscorrected below Column 5, line 7, strike out "d rating agent. withformaldehyde.", and insert the same after "dehy-" in column 7, line 10.

Signed and sealed this 14th day of May 1963.

( SEAL) Attest:

DAVID L. LADD ERNEST W. SWIDER Commissioner of Patents Attesting Officer

1. AS A NEW COMPOSITION OF MATTER, A SOLID POLYMER PRODUCED FROM ANOLEFIN SELECTED FROM THE GROUP CONSISTING OF PROPENE AND BUTENE-1, SAIDPOLYMER CONTAINING TERTIARY CARBON ATOMS AND BEING PREPARED BY THEPOLYMERIZATION OF THE OLEFIN IN THE PRESENCE OF A CATALYST AMOUNT OF ACATALYST PREPARED FROM A MIXTURE OF AN ORGANOALUMINUM COMPOUND AND ASALT OF OF A HEAVY METAL OF SUBGROUPS IVB-VIB OF THE PERIODIC TABLE, AND0.05-5% BY WEIGHT OF THE PRODUCT FORMED BY THE REACTION OF NONYL PHENOL,IN THE PRESENCE OF A MINERAL ACID DEHYDRATING AGENT, WITH A MEMBERSELECTED FROM THE GROUP CONSISTING OF FORMALDEHYDE, ACETALDEHYDE,ACETONE METHYLETHYL KETONE, CYCLOHEXANONE AND BENZALDEHYDE.